In order to improve anti-jamming performance of guidance weapons under poor electromagnetic environment, LMS array was applied in mid-course guidance link system which uses direct sequence spread spectrum communication. By making use of the feature of spread spectrum communication, the reference signal can be generated easily without pre-knowledge of training signal, and then the interference can be filtered in spatial domain. In addition, a model for guidance system was constructed to evaluate the effect on trajectory of guidance weapon using the anti-jamming method in mid-course guidance link. The simulation results show the effectiveness of the anti-jamming method.